Pipex Telephone Service
Wont Remove my deceased wife's name from their mailing list

My wife died in March and since then Pipex seem incapable of removing my wife's name from all their mailing lists and replacing it with my own. Both of my daughters have written to the company along with copies of wife's death certificate. Although I eventully received one letter addressed to myself with an apology for the error, they continue to send regular mail shots addressed to my late wife.